Coded data output apparatus

ABSTRACT

A coded data output apparatus comprises an image data input or generation section, a resolution parameter specifying section, a resolution parameter modifying section and an image data output section. The image data input or generation section inputs or generates data for a dot code image to be printed. The resolution parameter specifying section specifies parameter data relating to the resolution of the image data input or generated by the image data input or generation section. The resolution parameter modifying section modifies the parameter data relating to the resolution specified by the resolution parameter specifying section according to the characteristic specific to the applied plate making apparatus. The image data output section outputs the input or generated image data according to the parameter data relating to the resolution and modified by the resolution parameter modifying section.

BACKGROUND OF THE INVENTION

This invention relates to a data output apparatus for taking all elementdata into a computer, editing them in the computer and transforming theminto halftone dot images to be formed on printing plates in the step ofproducing image data to be used for making the printing plates.

More particularly, the present invention relates to a coded data outputapparatus for producing coded data to be used for forming dot codeimages to a plate making apparatus, which by turn produces printingplates carrying dot code images to be printed on printing media to makethe data in the images optically retrievable regardless of the type ofdata, be it audio data for voice and music, video data obtained by wayof cameras and other pieces of video equipment or coded digital dataproduced by personal computers, word processors and other dataprocessing apparatus. In short, a coded data output apparatus accordingto the invention is adapted to multimedia applications.

Conventional media for recording voice and music include magnetic tapesand optical discs. However, recorded copies in the form of tapecassettes and optical discs are considerably expensive and offered withhigh unit prices if recorded on a mass recording basis. Additionally,large space is typically required for storing tape cassettes and opticaldiscs. Furthermore, the transport of such recording media is timeconsuming and costly by any means particularly when they are mailed orshipped to remote areas.

This is true not only for audio media but also for video media thatcarry video images produced by cameras and other pieces of videoequipment and media that carry coded digital data obtained fromcomputers and word processors. In short, the so-called multimedia flowof information faces this problem.

In an attempt to solve this problem, EP 0,670,555 A1 (which correspondsto U.S. Ser. No. 08/407,018 filed by the assignee of the presentinvention) proposes a system for recording data in the form of atwo-dimensional pattern of coded dots produced as a coded data image bytwo-dimensionally arranging a plurality of dots that can be transmittedby facsimile and reproduced into a large number of copies at low costregardless of the type of data, be it audio data, video data or codeddigital data to make it adapted to multimedia applications, and also asystem for retrieving the data from the image.

According to the data format employed in the above system for coded dotdata of two-dimensional patterns, a dot code pattern comprises aplurality of blocks arranged vertically and horizontally fortwo-dimensional arrangement and each of the blocks contains a marker, ablock address and a data area for storing data for address errordetection and error correction and actual data. EP 0,7171,398 A3 (whichcorresponds to U.S. Ser. No. 08/571,776 filed by the assignee of thepresent invention) discloses a format for improving the density ofrecording coded dot data as will be described below by referring to FIG.1 of the accompanying drawings. Referring to FIG. 1 and according to theabove identified invention, pattern dots 278 are arranged between anyadjacently located markers 174 in the first direction, while addressdots 280 are arranged between any adjacently located markers 174 in thesecond direction. Each of the pattern dots 278 and address dots 280 hasa size equal to that of a data dot 282 to be arranged in a data area180. With such an arrangement for dot codes 170, the center of themarker 174 that provides a reference point for directionally determiningthe arrangement and reading data dots 282 can be identified easily andaccurately by means of a set of pattern dots 278 having a predeterminedpattern so that the original data can be retrieved without fail formultimedia applications.

Pattern dots, 278, address dots 280 and data dots 282 typically have asize of tens of several micrometers that may be 63 μm for example,although the size may be reduced to several micrometers depending on theapplication. While a number of techniques have been proposed to enhancethe quality of bar codes including Japanese Patent Application KOKAIPublication No. 5-15911 that discloses a technique of accuratelydetecting and controlling the inclination of a bar code printing head inorder to prevent degradation in the printing quality that can be givenrise to when an inclined head is used for printing and Japanese PatentApplication KOKAI Publication No. 5-54165 that teaches a bar codeprinting method with a printer having a low resolution, no comparabletechniques have been available for dot code printers that are requiredto print dot codes having a very fine dot arrangement with a very highlevel of positional accuracy.

On the other hand, the technique of desktop publishing (hereinafterreferred to as DTP) for producing originals of documents and imagesprepared by computers for printing. The DTP output is examined forcorrection, if necessary, by means of a monitor and then directlyprinted on a film to produce a printing plate by means of an imagesetter.

Thus, DTP can be applied to the coded data output apparatus forproducing coded data to be used for forming dot code images to a platemaking apparatus, which by turn produces printing plates carrying dotcode images to be printed on printing media to make the data in theimages optically retrievable for multimedia applications if they arevery finely drawn and the dots are required to show a very high degreeof positional accuracy.

Referring to FIG. 2A, data to be coded into dots for multimediaapplications are fed to a computer 102 by way of an input apparatus 100and then the computer 102 transforms the data into image data byreferring to the compression format, the error correction format, thedot code format and other reference data stored in an external memory104 and transmits the image data to an image setter 106, whichconstitutes a printing plate preparing system along with a printingplate exposure apparatus 108. Subsequently, the printing plate preparingsystem prints a dot code image on a film, which is then exposed to lightto make a printing plate. The produced printing plate is then put on aprinting machine 110 to produce copies of a printed matter that carriesdot codes.

Alternatively, a printing plate may be prepared without using a film asillustrated in FIG. 2B.

However, the above arrangement of preparing a printing plate cannot andshould not simply use the DTP output because the configuration of dotcodes have to be optimized for multimedia applications by taking theenvironment of handling dot codes into consideration, although theoptimization of dot code configuration has not been discussed to date.

BRIEF SUMMARY OF THE INVENTION

In view of the above described circumstances, it is therefore the objectof the present invention to provide a coded data output apparatus thatcan output a set of dot codes having an optimized configuration to makethem adapted to the environment where they are used.

According to the invention, the above object is achieved by providing acoded data output apparatus for producing an image data, including dotcoded data, out of multimedia data containing at least one of audiodata, video data and coded digital data, and supplies the image data toa plate making apparatus which is used to print the image data ontoprinting medium as optically readable dot codes, comprising: imageacquisition means for inputing or generating data as an image of a dotcode to be printed to acquire image data; resolution parameterspecifying means for specifying parameter data relating to theresolution of the image data acquired by the image data acquisitionmeans; resolution parameter modifying means for modifying theresolution-related parameter data specified by the resolution parameterspecifying means according to the resolution-related characteristics ofthe plate making apparatus; and image data output means for outputtingimage data acquired by the image acquisition means to the plate makingapparatus in accordance with the resolution-related parameter datamodified by the resolution parameter modifying means.

Thus, with a coded data output apparatus according to the invention, theresolution-related parameter data specified by the resolution parameterspecifying means are modified by the resolution parameter modifyingmeans according to the resolution-related characteristic of the platemaking apparatus and the image data for a dot code image are output bythe image data output means to the plate making apparatus in accordancewith to the modified resolution-related parameter data. Consequently,since the coded data output apparatus is provided with a function ofspecifying a resolution for the dot code image to be output according tothe resolution specific to the plate making apparatus, optimally codeddot data that are free from distortions due to resampling can beproduced by the coded data output apparatus.

Additional objects and advantages of the invention will be set forth inthe description that follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed out in theappended claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate a presently preferred embodimentof the invention and, together with the general description given aboveand the detailed description of the preferred embodiment given below,serve to explain the principles of the invention.

FIG. 1 is a schematic illustration of a known two-dimensional codepattern of dot codes.

FIGS. 2A and 2B are block diagrams of two conventional coded data outputapparatus for producing data for a dot code image to be printed formultimedia applications to which DTP is applied.

FIG. 3 is a block diagram of a preferred embodiment of the invention.

FIG. 4 is a schematic illustration of a resampling operation to beconducted for the purpose of the invention.

FIG. 5 is a schematic illustration of the relationship between the dotpitch and the CCD pixels to be used for the purpose of the invention.

FIG. 6A is a schematic illustration of an ideal arrangement of dots,where dots are located in close contact with each other.

FIG. 6B is schematic illustration of an undesired arrangement of dots,where dots are located too close to each other and the boundary isblurred with ink.

FIGS. 7A through 7D are schematic illustrations showing the 5C, 4S, 4Cand 3S pixel arrangements respectively.

FIG. 8 is a schematic illustration of a pixel configuration table to beused for the resolution parameter modifying section of the embodiment.

FIG. 9 is a schematic illustration of a dot arrangement to be used forthe purpose of the invention.

FIGS. 10A through 10D are schematic illustrations showing different dotcontours.

FIG. 11 is a graph showing the relationship between the percentage ofthe dot area and the occurrence rate of code reading errors.

FIG. 12 is a schematic illustration of dots having an ideal areapercentage.

FIG. 13 is a schematic illustration showing the positional relationshipbetween the center of a marker and that of a dot.

FIGS. 14A and 14B are schematic illustrations showing how thecoordinates of the center of a marker is transferred.

FIGS. 15A and 15B are schematic illustrations showing the limit for thenumber of blocks that can be read at a time.

FIGS. 16A and 16B are schematic illustrations showing the ratio of thesize of a printed dot to that of a pixel of an image pick-up device.

FIG. 17 is a flow chart of the operation of the resolution parametermodifying section of the embodiment.

FIGS. 18A through 18C are schematic illustrations showing the operationof the image data output section of the embodiment in terms of therelationship between the direction along which pixels are arranged andthe longitudinal direction of arranged dot codes.

FIGS. 19A through 19C are schematic illustrations also showing theoperation of the image data output section of the embodiment in terms ofthe relationship between the direction along which pixels are arrangedand the longitudinal direction of arranged dot codes.

FIG. 20 is a flow chart of the authoring operation of the image datainput or generation section of the embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Now, the present invention will be described in greater detail byreferring to the accompanying drawings that illustrate a preferredembodiment of the invention.

FIG. 3 is a block diagram of the preferred embodiment. A coded dataoutput apparatus 10 produces an image data, including dot coded data,out of multimedia data containing at least one of audio data, video dataand coded digital data, and supplies the image data to a plate makingapparatus 20 which is used to print the image data onto printing mediumas optically readable dot codes.

The plate making apparatus 20 prints a dot code image, which is a rasterimage, on a film or directly exposed to light to make a printing plate.(If the image is formed on a film, the image has to be transferred ontoa printing plate, which is then exposed to light.) Thus, the platemaking apparatus 20 corresponds to the image setter 106 and the platemaking apparatus 108 of FIG. 2A and also to the plate making apparatus108 in FIG. 2B.

On the other hand, the coded data output apparatus 10 corresponds to theinput apparatus 100, the computer 102 and the external memory 104 inFIG. 2A or FIG. 2B and comprises an image data input or generationsection 12, an image data output section 14, a resolution parameterspecifying section 16 and a resolution parameter modifying section 18.

The image data input or generation section 12 operates to input codedimage data prepared by an external dot code preparing apparatus or thelike (not shown) or encode multimedia data to be entered into codes togenerate image data of the codes.

The image data output section 14 transforms coded image data into thosewith a format that can be recognized by the image setter 106 or theplate exposure apparatus 108 and sends them out.

The resolution parameter specifying section 16 specifies parametersnecessary for generating coded images that provide dot codes with adesired size on a printed matter that is a final output of theapparatus. For example, the parameters to be used for the purpose of theinvention include the size of each dot of dot codes and the number ofpixels to be used for forming a dot and the resolution. The resolutionis used to indicate of the size of each pixel for forming a coded imageon the image setter. Typically, the resolution is expressed in terms ofthe number of pixels per inch or dpi (dot per inch).

The resolution parameter modifying section 18 modifies the parametersspecified by said resolution parameter specifying section 16 accordingto the data characteristic to the plate making apparatus 20 to be usedwith the coded data output apparatus 10. For example, if the resolutionspecified by the resolution parameter specifying section 16 does notagree with that of the image setter, it respecifies the resolution tomake it agree with that of the image setter.

More specifically, the coded data output apparatus 10 provides the dotcode image to be printed with a specific format such as TIFF formatbefore the corresponding image data coming from the image data input orgeneration section 12 are transmitted to the plate making apparatus 20and have the image data output section 14 transform it into a formatsuch as a postscript format. With this arrangement, the image can becomedistorted by the resampling operation if the resolution of the imagedata does not match that of the plate making apparatus 20. In order toprevent such distortion, the image data have to be made to match theresolution of the plate making apparatus 20 that is specific to thelatter by using characteristic data on the resolution of the latter.

The image setter 106 can show a resolution specific to it and differentfrom those of other image setters. Therefore, the resolution of an imagesetter can vary between 2,400 dpi and 3,000 dpi of beyond them. If thedata transmitted to the image setter 106 corresponds to straight lineconsisting of 10,000 pixels, they covers a stretch of about 106 mm ifthe resolution is 2,400 dpi and about 85 mm if the resolution is 3,000dpi. Thus, the finally produced images may show varied sizes if nospecific arrangements are provided for the resolution.

Assume here that a resolution of 2,400 dpi is specified by way of thecomputer 102 of the coded data output apparatus 10 to draw a broken linewith 10,000 pixels including 5,000 black pixels and 5,000 white pixelsarranged alternately in a sequence of a white pixel, a black pixel, awhite pixel, a black pixel, . . . The computer 102 tries to produce anoutput for an about 106 mm long broken line where each line segment andeach white interval have a length of 10.6 μm. However, if the imagesetter 106 receiving the output has a resolution of 3,000 dpi, it canonly produce a broken line where each line segment and each whiteinterval have a length of 8.5 μm to make the total length of the brokenline equal to 85 mm. Then, the coded data output apparatus cannotproduce the intended image because the image is dimensionallysignificantly altered.

The computer 102 can alternatively provide an output with a differentnumber of pixels to draw the image having the intended size. Thus, thecomputer 102 can choose either an image with the intended size or aconstant resampling size. If an image with the intended size is chosenand an output for the image is produced, then, the 10,000 pixels areresampled to replace the 10,000 pixels by 12,500 pixels, whichconsequently give rise to a distorted image as shown in FIG. 4.Referring to FIG. 4, although the computer tries to produce an outputfor black and white bars arranged alternately at regular intervals asshown in the upper half of FIG. 4, the output inevitably produces barsthat are arranged at irregular intervals.

Finely defined codes such as dot codes are required to be free fromdistortions due to resampling. In the case of a situation where thepresent invention is applied for producing dot codes with a dot pitch ofabout 63 μm by means of an image setter 106 with a resolution of 2,400dpi, the interval separating two adjacent dots is constituted by 6pixels. Conversely, for outputting a dot code with a dot pitch of 60 μm,an output apparatus that can provide pixel pitches adaptable to all thecommon divisors has to be used and the image setter 106 is required tohave a resolution of 2,540 dpi.

Now, the operation of the resolution parameter modifying section 18 willbe described below.

Firstly, the process of optimizing the dot code as a function of thenecessary conditions for reading data will be described.

If, for example, an image pick-up device such as CCD is used to readcoded data in the form of bar codes that are arranged with an intervalof T, the image is projected on the focal plane of the CCD periodicallywith a period of TM, where M is the optical magnification.

In order for the coded data to be read without fail with the period ofTM, it will be understood from the sampling theorem that the CCD pixelinterval X needs to be smaller than TM. However, the CCD pixel intervalX is required to satisfy the requirement below in order to make the barcode readable if tilted by 45° in order to make it adapted to situationswhere the bars and the pixel arrangement of the CCD are accidentallyrotated. ##EQU1##

On the other hand, in the case of dot codes to which the presentinvention is applied and where data are expressed by dots, the CCE pixelinterval X is required to satisfy the requirement expressed below byusing the dot pitch T in view of the fact that the area occupied by dotsis smaller than a half of the area of the pixels if the center of eachdot is covered by a pixel. ##EQU2## or

    X<TM×0.63

Thus, if squares (that correspond to CCD pixels), each having a size of0.63 times of the dot pitch T and being arranged to cover the center ofa dot 22, are arranged in a manner as shown in FIG. 5, more than 50% ofthe surface area of each of the CCD pixels is occupied by a dot 22.

The numerical value of 0.63 represents an ideal situation where dots 22are true circles having a diameter equal to the pitch of arrangement ofpixels, although the arrangement may be subjected to more harshrequirements due to the profile of the medium where dot codes are formedand the complexity of the process of forming dot codes (due to factorsincluding the state of the ink and that of the toner if they are formedby printing). Thus, it will be necessary for the sampling operation toprovide a pixel interval smaller than a half of the dot pitch on a planewhere the image is picked up in order for the dot codes to be readcorrectly.

On the other hand, dot codes for which this embodiment is used are basedon square blocks 272 provided with markers 174 arranged at all the fourcorners as shown in FIG. 1 and read on a block by block basis. A dotcode is formed by a plurality of blocks arranged continuously andtwo-dimensionally. Thus, the dot code image taken by the CCD desirablycontains at least a block 272. In other words, all the dots includingthe markers that are contained in a block have to be found in the pickedup image. Additionally, in view of the operation of processing all theblocks of a dot code taken up by scanning, it will be understood thatthe larger the number of blocks taken by a single image pick-upoperation, the more advantageous from the viewpoint of scanning speed.

All in all, the dot pitch T is preferably not greater than 5 pixels forthe CCD. A greater number may not feasibly be used.

Under the above described conditions, the dot pitch T can be defined asfollows in terms of the distance of n minimum pixels of an image setterwith a resolution of R [lines/mm]. ##EQU3##

The resolution parameter modifying section 18 modifies the dot pitch soas to make it satisfied the above requirement.

Now, the configuration of each dot of a dot code will be described.

Since a dot code is realized by arranging dots at a high pitch, they areideally so arranged that any two adjacent dots are held in close contactwith each other as shown in FIG. 6A. However, when dot codes are formedby printing, each dot can become blurred as in FIG. 6B if adjacent dotsare in contact with each other so that they may not be correctly read.The ink can flow out into white areas to produce black areas, which maythen be mistaken for dots with a considerably high probability.

Therefore, it is desirable that dots are completely separated from otheron the printing plate. Differently stated, dots preferably have adiameter smaller than the dot pitch rather than a diameter equal to thedot pitch (which will be referred to as ideal diameter hereinafter).

Additionally, each dot ideally is a true circle, although it isimpossible to draw a true circle from the viewpoint of the resolution ofthe image setter because a dot is formed by pixels with a size of about10 μm.

While the above arrangement may provide a satisfactory resolution for animage that is observed under ordinary conditions, dot codes to which thepresent invention is applicable have a size between 50 and 60 μm andhence a minimum pixel of 10 μm is not satisfactory in terms ofresolution.

In order to cope with this problem, the present invention proposes acircle approximately drawn by a set of minimum pixels. FIGS. 7A through7D illustrate show how dots are formed at a pitch of 5 pixels. Note thateach of the circles in these figures represents the contour of an idealdot and each of the hatched squares represents a pixel in outputapparatus.

In FIG. 7A, the dot has a size of five pixels, which is equal to thediameter of the ideal dot. This arrangement will be referred to as5C-type pixel arrangement because the pixels at the four corners of thesquare corresponding to the circle are removed to make the contourcloser to the true circle.

With the 5C-type pixel arrangement, any attempt to reproduce the dotwith ink will result in a blurred dot where ink flows into theadjacently located dots and also into white areas surrounding thecontact points of the dot. Then, the average size of the printed dots isenlarged to give rise to a high under-error rate.

Under-error as used herein refers to an error of mistaking a whitenon-dot area for a dot, which is observed frequently when the producedfinal image suffers from under-exposure and the image is dominated by adark tone.

Conversely, an error of not detecting one or more than one dots becauseof a pale image is referred to as over-error.

In FIG. 7B, the dot has a size of four pixels or a square form realizedby 4×4 pixels. This arrangement will be referred to as 4S-type pixelarrangement.

Similarly, FIG. 7C shows a 4C-type pixel arrangement and FIG. 7D shows a3S-type pixel arrangement.

Of these arrangements, the 4S-, 4C- and 3C-type pixel arrangementsprovide dots that do not interfere with each other, the dot size beingdiminished in the above mentioned order.

On the other hand, the image setter exposes the film to laser beams and,therefore, the size of pixels for forming dots can be varied as the beamdiameter changes. If, for example, a laser beam having a relativelylarge diameter is used at a high intensity for exposure, thephotochemically developed pixels are apt to show a large diameter. Morespecifically, if the image setter 106 draws a spot on a film and has aresolution of 2,400 dpi, the film is supposed to show a spot with adiameter of 10.6 μm when developed. However, the spot can become aslarge as 12 μm if a blurred beam is used and/or the developing solutionis not agitated sufficiently for development or has been deteriorated byuse. In general, while efforts are paid to regulate the image setter 106into optimal conditions in order to avoid such situations in the outputcenter, no standards have been provided for the regulating operation andvarious techniques for determining the photosensing characteristics ofthe film and regulating the image developing conditions are currentlytried on an ad hoc basis.

Thus, if a same original and an image setter having a standardizedresolution are used, the obtained final output images can show variedtones and different pixel sizes.

In order to cope with this problem, this embodiment is designed todetermine if the image setter (plate making apparatus 20) tends toenlarge or diminish pixels on the basis of the data characterizing theperformance of the image setter and, if it tends to enlarge pixels, itchoose a pixel arrangement that produces small dots.

This operation of choosing an optimal pixel arrangement is carried outby the resolution parameter modifying section 18, for example, using atable as illustrated in FIG. 8. The table is designed for use when dotcodes are formed with a dot pitch of about 60 μm.

Parameters including the different resolutions of the image setter suchas 2,400 dpi, 2,540 dpi and 3,000 dpi are fed from the resolutionparameter specifying section 16 to the resolution parameter modifyingsection 18. If the resolution of 2,540 dpi is used for a dot pitchclosest to 60 μm, the resolution parameter modifying section 18 feedsthe image data input or generation section 12 with the parametersnecessary for producing dots with the dot pitch of 60 μm and the 5C-typepixel arrangement. Likewise, the dot pitch of 63.5 μm that is closest to60 μm and the 5C-type pixel arrangement are used for the resolution of2,400 dpi, whereas the dot pitch of 59.3 μm and the 6C-type pixelarrangement are used for the resolution of 3,000 dpi and fed to theimage data input or generation section 12.

If, however, the image setter or the plate making apparatus 20 tends toproduce larger pixels for some reason or other, then the embodimentdetermines the tendency on the basis of the data characterizing theperformance of the plate making apparatus 20 and switches to the 4S-typepixel arrangement for 2,400 dpi or 2,540 dpi. If the tendency ofproducing larger pixels continues, the embodiment further switches tothe 4C-type pixel arrangement.

Various techniques may be used for determining if the dots output fromthe image setter tend to grow. For instance, a reference pattern may beprinted on a margin that is removed from the printed final product sothat it may be referred to in order to determine if the tendency ofgrowing dots exists or not. Note that the reference pattern includessmall dots for determining how the smallest pixel unit.

Now, the dot size will be described.

Ideally, data are taken in with the smallest possible number of pixelswithout error when the CCD sampling is conducted with the dot size of ahalf of the dot interval. However, the size will have to be made smallerin most cases because the CCD sampling becomes short of number if thesize is greater than a half of the dot interval but the problem of areduced allowable amount of data arises as will be described hereinafterif the CCD pixel aperture is reduced (in relative terms, although theCCD pixels do not vary and therefore the dot size increases if the CCDpixels are unvaried). In other words, it is advantageous to use arelatively small dot size. The CCD sample interval has a limit of a halfof the dot size, provided that data can be taken in with the smallestpossible number of pixels.

On the other hand, in order for dot data taken in with a CCD pixelaperture equal to a half of the dot interval to be optically resolved,each dot has to have an area not smaller than a half of the aperture. Inother words, in FIG. 5, the CCD pixel 24 is not determined to be blackunless the dot occupies more than half of the area of the pixel 24.

Referring to FIG. 9, each square defined by four tangent linesseparating adjacently located pixels is referred to a dot existing areahereinafter. Then, each dot area contains a dot.

Now, referring to FIG. 10A, if dots are arranged at an interval of fivepixels and each dot is formed with 3×3 pixels (note that each square inFIGS. 10A through 10D represents a pixel of the image setter), each dottakes 36% of the corresponding dot existing area (hereinafter to beexpressed as a dot area percentage of 36%).

If the dots are printed accurately for codes or, more specifically, ifthe film produced accurately by the image setter is accurately copied ona printing plate and the printing operation is conducted accurately bymeans of the printing plate, dots of 3×3 pixels will be accuratelyreproduced by printing. The dots will not be resolved, however, if theyare sampled by a CCD with a sampling pitch equal to a half of the dotpitch. In other words, these dots cannot be used for codes with theabove arrangement.

However, there can be cases where codes are read with the abovearrangement if the film is exposed to a beam that tends to grow or thedot diameter tends to grow due to under-exposure at the time of copyingthe film on the printing plate until the dot area percentage exceeds 50%as shown in FIG. 10B. In shorts, dot codes are read correctly if the dotarea percentage exceeds 50% in the final printed matter that carriescodes.

On the other hand, the dot area percentage is 48% with the 4C-type pixelarrangement as shown in FIG. 10C. However, if dots grows in the abovedescribed manner, the dot area percentage can rise to about 80% as shownin FIG. 10D, where dots can interfere with each other to raise the codereading error rate.

FIG. 11 is a graph showing the relationship between the dot areapercentage and the code reading error rate.

As seen from the graph, the reading error rate is low when the dot areapercentage is found between about 50% and about 80% and minimized whenthe dot area percentage is about 60%. Thus, while the dot of FIG. 10Amay not be read because of its poor dot area percentage but it becomesreadable when it grows to show a dot area percentage of about 50% asshown in FIG. 10B. On the other hand, if a dot is formed with a dot areapercentage of 50% as shown in FIG. 10C without expecting a growth on thepart of the dot, the dot may grow until the area percentage exceeds 80%and become unreadable as shown in FIG. 10D.

As described above, the reading error rate is minimized when the dotarea percentage is about 60%. Dots with this ideal area percentage havea diameter equal to 0.88 of the dot interval as shown in FIG. 12. Thus,the resolution parameter modifying section 18 selects a pixelarrangement from the table of FIG. 8 in such a way that the final outputshows dots with an area percentage closest to this ideal value.

Now, the shift of the center of marker 174 will be described.

A dot code to which the present invention is applicable is constitutedby data dots 282 having a configuration as described above and a marker174 far greater than each data dot 282. The marker 174 has a diameterequal to five times of the dot pitch or 25 pixels and the coordinates ofthe center thereof has to be phase-matched with those of the center ofeach data dot 282.

FIG. 13 is an illustration showing the relationship between the marker174 and the data dot 282. Referring to FIG. 13, the straight lines ofthe lattice-like pattern defines pixel cells of the image setter. Thus,the marker 174 and the data dot 282 are quasi-circles formed with pixelcells.

Assume here that the data dot 282A has the 3S-type pixel arrangement. Asseen from the drawing, the center of the pixel located at the center ofthe group of pixels that form the data dot agrees with the center of thedot. Thus, the coordinates of the center of the marker 174 having adiameter equal to that of a quasi-circle of the 25 pixels that is an oddnumber of times of the size of each pixel and the coordinates of thecenter of the data dot 282A with the 3S-type pixel arrangement arephase-matched, the center of each circle being indicated by a white spotin FIG. 13.

On the other hand, if the data dot 282B has the 4S-type pixelarrangement, the center of the group of pixels that form the data dot islocated on a boundary line separating adjacent pixels. Therefore, thecenter of the data dot 282A and that of the data dot 282B are displacedby a half of the size of a pixel and hence the coordinates of the centerof the marker and those of the center of the data dot 282B are notphase-matched.

Thus, if the data dot 282 has a diameter equal to an even number oftimes of the size of a pixel as in the case of the 4S-type pixelarrangement, the marker having a diameter equal to an odd number oftimes of the size of a pixel has to be displaced by a distance of a halfof the pixel size both in the X- and Y-directions in order to place thecenter of the marker 174 on a boundary line. The resolution parametermodifying section 18 of this embodiment modifies the marker illustratedby a white area and hatched areas in FIG. 14A to show a contour asillustrated in FIG. 14B, where the center of the marker is located on aboundary line. The contour as illustrated in FIG. 14B corresponds to awhite area and black areas in FIG. 14A.

Now, the number of blocks that can be read within a screen will bedescribed.

If the image pick-up apparatus has a screen with X- and Y-directionaldimensions equal to Nx pixels and Ny pixels respectively and dot codesare read by scanning the camera in the Y-direction at a rate of Nfframes per second in such a way that each block occupies Bx and Bypixels in the X- and Y-directions respectively in the image pick-upapparatus, the number of blocks taken up in a frame will be

Nx/Bx in the X-direction and

Ny/By in the Y-direction.

However, with dot codes to which the present invention is applicable,each block will not be successfully read if the entire block is entirelyprojected on the screen.

To satisfy the above condition, the number of blocks that can be read ina frame will be

int(Nx/Bx)-1 in the X-direction and

int(Ny/By)-1 in the Y-direction,

where "int" represents a function for producing an integer by discardingthe fraction of the argument.

Referring to FIG. 15A, the hatched area corresponds to the area taken bythe CCD and each circle represents a marker 174. Thus, a pair of blocks722 are found in the image pick-up area 26 of the CCD and, therefore,these two block are read.

To the contrary, if the dot code has a large area, it can overflow fromthe CCD image pick-up area 26 as shown in FIG. 15B. In the case of FIG.15B, there is no block that has four markers arranged at the fourcorners and located within the image pick-up area 26 and hence no blockcan be read.

Therefore, each dot code has to be defined in terms of the block size insuch a way that an entire block can be projected on the CCD screen. Inthis embodiment, the resolution parameter modifying section 18 operatesto define the dot interval so as to maximize the number of blocksprojected on the screen.

Now, the relationship between the embodiment and the medium for carryingthe final output will be described.

Generally, the profile of each printed dot on the medium variesdepending on the type of the medium, which can be paper or film. If dotsare printed on a sheet of paper, they tend to grow. If they are printedon sheet of film, a seal or a sheet of coated paper, the printed dotswill not grow because the ink would not permeate. Thus, the resolutionparameter modifying section 18 can modify the dot arrangement dependingon the type of the medium, taking the possibility of dot growth intoconsideration.

Now, the relationship between the embodiment and the aspect ratio of theimage pick-up apparatus will be described.

CCDs generally do not carry out the sampling operation for a square. Forexample, NTSC system cameras have an aspect ratio different from that ofa square. If the sampling operation is carried out in an area that isnot a square, the picked up image will inevitably be distorted. If around dot is picked up by a CCD having an aspect ratio of 3:2, a flatimage is reproduced on the screen as shown in FIG. 16A because thepixels of the dot are sampled at a rate of 3 horizontally and 2vertically.

In this embodiment, the resolution parameter modifying section 18specifies the dot shape and the dot interval in such a way that the theyare optimized when dot codes are picked up with the aspect ratio of theimage pick-up apparatus. In other words, an elliptical shape and acorresponding dot interval is specified for dots as shown in FIG. 16B.

FIG. 17 is a flow chart of the operation of the resolution parametermodifying section 18.

Firstly, an approximate dot pitch is selected (step S10) and then theresolution of the image setter is manually input (step S12). Datacharacteristic of the image setter such as the tendency of growing orslimming dots are input (step S14).

Then, the resolution parameter modifying section 18 determines anoptimal pixel arrangement including the number of horizontally arrangedpixels, that of vertically arranged pixels and the dot pitch byreferring to the pixel arrangement table 28 (step S16). Finally, if thecoordinates of the center of the markers are displaced and hence has tobe corrected, an optimal pixel arrangement is determined also for themarkers by referring to the target pixel table 30 for marker correction(step S18).

Now, the operation of the image data output section 14 will bedescribed.

Firstly the directions along which pixels are arranged and thelongitudinal direction of dot codes show a relationship as will bedescribed below.

FIG. 18A shows dot codes printed in an ordinary manner, where thedirection of pixel arrangement agree with the longitudinal direction ofdot codes. If dot codes are printed aslant as shown in FIG. 18B, theresampling operation will be adversely affected as described earlier.

To cope with this situation, the image data output section 14 of thepresent embodiment produces an output for obliquely arranged dot codesby shifting the rows of blocks without shifting the direction of blockarrangement as shown in FIG. 18C so that consequently the pixelarrangement defined by the image data input or generation section 12agrees with the pixel arrangement fed to the plate making apparatus 20(image setter).

Alternatively, the image data output section 14 may keep the slantedoriginal dot code arrangement but enlarge the dot codes only to such anextent that they are not adversely affected by resampling. In otherwords, the effect of resampling can be reduced by increasing the numberof dot resampling and, therefore, dot codes are enlarged to that end bydetermining an optimal magnification through arithmetic operations.

FIGS. 19A through 19C illustrate examples where the direction of dotcode arrangement and that of pixel arrangement of the image setter arenot in parallel with each other. While bar codes are used in thedrawings for the purpose of simplification, the underlying idea isapplicable to dot codes without any modification.

FIG. 19A illustrates the positional relationship between codes and thepixel array of the image setter. In FIG. 19A, the broken lines shows thelongitudinal direction of the pixel array of the image setter and theblack blocks are used for codes (note that the width of each of theblack block for codes is equal to the resolution of the image setter).FIG. 19B shows a typical result of resampling carried out for the codesof FIG. 19A by the image setter. As shown, the black blocks for codesare distorted almost by a half of the width of each black block. If theblack blocks are arranged in parallel with the pixel arrangement of theimage setter, the codes may be reproduced without distortion. FIG. 19Cshows an example of resampling with a doubled rate, keeping thepositional relationship between the pixel array and the black blocks.The distortion is limited to a quarter of the width of each black blockin this example.

If, for instance, the code reading apparatus can read codes correctly upto a distortion level equal to a quarter of the width of each blackblock, the distorted codes can be accommodated by doubling the coderesampling rate. In other words, no reading error will occur if thecodes are enlarged to a double size for printing.

Finally, the authoring operation of the image data input or generationsection 12 will be described by referring to FIG. 20.

If audio data are compressed to dot codes for printing, the space thatcan be allocated to codes in a printed matter may be limited whenletters, pictures and graphs are also printed there. Then, the editorwill have to decide the layout for allocating space to dot codes.

If such is the case, the size of dot codes has to be known in the stepof DTP operation because the length of dot code can vary depending onthe amount of input data to be coded into dots. The operation of codinginto dots including a data compression process takes time and,therefore, the size of dot codes has to be approximately calculated todetermine the layout before the completion of the coding operationincluding a data compression process.

To assist the layout operation, as data are input (step S20), the amountof data is determined by arithmetic operations (step S22). At this time,the resolution parameter modifying section 18 receives data on theresolution of the plate making apparatus 20 (step S30) to determine thedot interval in a manner as described earlier (step S32). Then, theimage data input or generation section 12 determines the size of dotcodes on the basis of the computed amount of data and the determined dotinterval (step S24).

The present invention is applicable not only to the operation of makinga printing plate but also to the operation of a printer if a printerhaving a satisfactory resolution is developed in future, although such aprinter is not currently available. Then, the dot code arrangement maybe optimized for the printer by means of the computer so that dot codesmay be directly printed out from the printer.

While the present invention is described in detail by way of a preferredembodiment, the present invention is not limited thereto by any meansand it may be modified and/or applied in various ways without departingfrom the scope of the invention.

Now, the present invention will be summarized as follows.

(1) A coded data output apparatus for producing an image data, includingdot coded data, out of multimedia data containing at least one of audiodata, video data and coded digital data, and supplies the image data toa plate making apparatus which is used to print the image data ontoprinting medium as optically readable dot codes, comprising:

image acquisition means for inputing or generating data as an image of adot code to be printed to acquire image data;

resolution parameter specifying means for specifying parameter datarelating to the resolution of the image data acquired by the image dataacquisition means;

resolution parameter modifying means for modifying theresolution-related parameter data specified by the resolution parameterspecifying means according to the resolution-related characteristics ofthe plate making apparatus; and

image data output means for outputting image data acquired by the imageacquisition means to the plate making apparatus in accordance with theresolution-related parameter data modified by the resolution parametermodifying means.

Thus, the coded data output apparatus is capable of specifying aresolution for the coded image data to be output according to theresolution of the plate making apparatus so that dot codes can be outputunder optimal conditions and without distortions due to resampling.

(2) The coded data output apparatus according to (1), wherein theresolution parameter modifying means includes pixel arrangementspecifying means for specifying a pixel arrangement for pixels to beassigned to each dot constituting the smallest data unit in dot codes tobe printed on the printing medium according to the resolution-relatedcharacteristics in order to modify the parameter data relating to theresolution and specified by the resolution parameter specifying meansand dot interval specifying means for specifying the dot interval fordots constituting the smallest data unit in dot codes to be printed onthe printing medium according to the resolution-related characteristics.

Thus, the dot interval and the pixel arrangement for pixels to beassigned to each dot constituting the smallest data unit in dot codescan be optimized simultaneously according to the resolution of the platemaking apparatus.

(3) The coded data output apparatus according to (2), wherein the pixelarrangement specifying means further includes a reference table to bereferred to for determining the pixel arrangement for pixels to beassigned to each dot constituting the smallest data unit in dot codes tobe printed on the printing medium on the basis of the parameter datarelating to the resolution and specified by the resolution parameterspecifying means and the resolution-related characteristics so that anoptimal pixel arrangement may be selected according to theresolution-related characteristics by referring to the reference table.

Thus, the pixel arrangement specifying means can select an optimal pixelarrangement from the table without the need of cumbersome arithmeticoperations.

(4) The coded data output apparatus according to (2), wherein the dotinterval specifying means further includes a reference table to bereferred to for determining the pixel interval for pixels to be assignedto each dot constituting the smallest data unit in dot codes to beprinted on the printing medium on the basis of the parameter datarelating to the resolution and specified by the resolution parameterspecifying means and the resolution-related characteristics so that anoptimal pixel interval may be selected according to theresolution-related characteristics by referring to the reference table.

Thus, the dot interval specifying means can select an optimal pixelinterval from the table without the need of cumbersome arithmeticoperations.

(5) The coded data output apparatus according to (2), wherein the pixelarrangement specifying means specifies an optimal pixel arrangement bymodifying the geometrical arrangement of pixels for each dot whenspecifying the pixel arrangement for pixels to be assigned to each dotconstituting the smallest data unit in dot codes to be printed on theprinting medium.

Thus, the arrangement of pixels constituting each dot of dot codes fromthe output apparatus can be modified in such a way that an optimal shapesuch as circle may be used for dots to make them closest to the shape ofthe codes when they are read.

(6) The coded data output apparatus according to (5), wherein the pixelarrangement specifying means specifies an optimal pixel arrangement bymodifying the geometrical arrangement of pixels for each dot in such away that the diameter of each dot constituting the smallest data unit indot codes to be printed on the printing medium is smaller than the idealdistance separating adjacent dots.

Thus, pixels are arranged in such a way that the diameter of each dot issmaller than the ideal distance separating adjacent dots so that dotsare completely separated from each other and non-dot areas are notmistaken for dots.

(7) The coded data output apparatus according to (6), wherein each dotis formed by arranging a number of pixels in such a way that thediameter of each dot specified by the pixel arrangement specifying meansis greater than a half of the ideal distance separating adjacent dots.

Thus, each dot is formed by arranging a number of pixels in such a waythat the diameter of each dot is greater than a half of the distanceseparating adjacent dots so that dots can be read with a sampling ratesufficient for the reading operation.

(8) The coded data output apparatus according to (6), wherein each dotis formed by arranging a number of pixels in such a way that the surfacearea of each dot specified by the pixel arrangement specifying means isbetween 50% and 80% of the square of the ideal distance separatingadjacent dots.

Thus, the number of pixels for forming a dot is controlled by the dotarrangement and selected in such a way that the surface area of each dotspecified by the pixel arrangement specifying means is between 50% and80% of the square of the ideal distance separating adjacent dots. Thus,an optimal dot size that minimizes the reading error rate can beselected.

(9) The coded data output apparatus according to (2), wherein the dotinterval specifying means specifies a dot interval in such a way thatthe dot interval of the dots to be printed on the printing medium isequal to the smallest pixel interval of the plate making apparatusmultiplied by an integer.

Thus, the dot interval specifying means determines by arithmeticoperations that the dot interval has a pitch equal to the smallest pixelinterval of the image setter multiplied by an integer and therefore noresampling occurs on dot codes.

(10) The coded data output apparatus according to (2), wherein the dotinterval specifying means specifies a dot interval according to theinterval of discrete aperture sampling of the image pick-up means foroptically reading the dot codes printed on the printing medium.

Thus, the dot interval specifying means modifies the dot pitch (dotinterval) of dot codes, taking the sampling by the image pick-up meansinto consideration so that the data can have an optimal size thataccommodates the sampling of the CCD.

(11) The coded data output apparatus according to (10), wherein the dotinterval specified by the dot interval specifying means satisfies theformula of ##EQU4## where n is the pitch of the smallest pixels of theplate making apparatus (n: integer), R is the resolution of the platemaking apparatus, M is the optical magnification of the image pick-upmeans and X is the pixel interval of the image pick-up means when thecoded data output apparatus outputs image data.

Thus, if n is the pitch of the smallest pixels of the plate makingapparatus (n: integer), R is the resolution [lines/mm] of the platemaking apparatus, M is the optical magnification of the image pick-upmeans and X is the pixel interval of the image pick-up means, thesmallest pixels output from the image setter is projected to a size ofM/RX on the CCD so that the dot diameter is made greater than the sizeof two pixels on the image pick-up apparatus to provide a resolutionsufficient for a code reading operation when (2RX/M)<n is satisfied.Additionally, the dot diameter is made smaller than five pixels on theimage pick-up apparatus to make the block or blocks to be readcompletely visible and to allow a high density data recording whenn<(5RX/M) is satisfied.

(12) The coded data output apparatus according to (10), wherein each ofthe dot codes is formed by two-dimensionally arranging a plurality ofblocks, each comprising a data dot pattern arranged in correspondence tothe contents of data for the multimedia data and a marker arranged witha predetermined positional relationship with a corresponding the datadot pattern for determining reference point for the operation of readingthe data dot pattern and

the dot interval specifying means specifies a dot interval in such a waythat the number of the block is maximized in the light receiving planeof the image pick-up means.

Thus, for reading data on a block-by-block basis, the dot interval canbe modified according to the resolution of the image setter to maximizethe number of blocks that can be read on the screen so that a largeamount of data can be read with a single image pick-up operation.

(13) The coded data output apparatus according to (1), wherein each ofthe dot codes is formed by two-dimensionally arranging a plurality ofblocks, each comprising a data dot pattern arranged in correspondence tothe contents of data for the multimedia data and a marker arranged witha predetermined positional relationship with a corresponding the datadot pattern for determining reference point for the operation of readingthe data dot pattern and

the resolution parameter modifying means further includes markerposition correcting means for correcting the position of the markerrelative to the data dot pattern according to the modification of theparameter data relating to the resolution and specified by theresolution parameter specifying means according to the appliedresolution-related characteristics specific to the plate makingapparatus.

Thus, the position of the marker is corrected by taking the dot intervaland the pixel arrangement for dots into consideration when modifying thepixel arrangement according to the resolution of the image setter to beused for the output apparatus.

For example, if the 4S-pixel arrangement is selected, the center of thedot is located on a boundary line separating pixels for the dot. On theother hand, if the 3S-type pixel arrangement is selected, the center ofdot is located on the center of one of the pixels of the dot.

(14) The coded data output apparatus according to (13), wherein themarker position correcting means further includes a marker correctiontable specifying the relationship between the resolution-relatedcharacteristics specific to the plate making apparatus and the pixelsconstituting the marker so that it corrects the pixel value by a 0.5pixel unit by referring to the marker correction table.

Thus, if the marker needs correction, the marker position correctingmeans selects the values of the pixels to be corrected on the markercorrection table on the basis of the pixel arrangement when nocorrection is necessary and modifies the values by referring to thetable so that the coordinates of the center of each marker can be movedby a 0.5 pixel without the need of cumbersome arithmetic operations.

(15) The coded data output apparatus according to (1), wherein each ofthe dot codes is formed by two-dimensionally arranging a plurality ofblocks, each comprising a data dot pattern arranged in correspondence tothe contents of data for the multimedia data and a marker arranged witha predetermined positional relationship with a corresponding the datadot pattern for determining reference point for the operation of readingthe data dot pattern and

the image data output means includes block arrangement specifying meansfor causing the direction of the blocks constituting the dot codes agreewith the direction of the pixel arrangement of the plate makingapparatus if it recognizes that the direction of the pixel arrangementdoes not agree with the longitudinal direction of the dot codes to beprinted when it outputs the image data corresponding to the dot codes.

Thus, if the direction of the pixel arrangement of the output apparatusand the longitudinal direction of the dot codes are not parallelrelative to each other for the output operation of the output apparatus,it corrects the direction of the dot codes to make it agree with thedirection of the pixel arrangement so that the dots in the blocks arenot resampled although the direction of the code arrangement isapparently not modified.

Therefore, the longitudinal direction of the dot codes of FIG. 18C isupwardly inclined by 45° at the right side, the blocks constituting thecodes can be handled as if the longitudinal direction were inclined by0° and agrees with the direction of the pixel arrangement of the imagesetter.

(16) The coded data output apparatus according to (1), wherein each ofthe dot codes is formed by two-dimensionally arranging a plurality ofblocks, each comprising a data dot pattern arranged in correspondence tothe contents of data for the multimedia data and a marker arranged witha predetermined positional relationship with a corresponding the datadot pattern for determining reference point for the operation of readingthe data dot pattern and

the image data output means includes dot interval regulating means forregulating the dot code interval so as not to cause dot code readingerrors to occur if the image data corresponding to the dot codes areresampled by the pixel interval of the plate making apparatus if itrecognizes that the direction of the pixel arrangement of the platemaking apparatus does not agree with the longitudinal direction of thedot codes to be printed when it outputs the image data corresponding tothe dot codes.

Thus, if the direction of the pixel arrangement of the output apparatusand the longitudinal direction of the dot codes are not parallelrelative to each other for the output of the output apparatus, itdetermines by computation a dot pitch that does not interfere with thedot code reading operation if the dots are resampled and automaticallyoutputs the determined dot pitch (dot diameter) to avoid any adverseeffect of resampling.

(17) The coded data output apparatus according to (16), wherein the dotinterval regulating means includes means for regulating the dot codeinterval without altering the direction of the dot codes and thedirection of the blocks.

Thus, the codes can maintain the rectangular shape and the direction ofthe codes are not altered so that the code may be turned withoutchanging the appearance.

(18) The coded data output apparatus according to (1), wherein theresolution parameter modifying means includes means for estimating theshape of each dot constituting the smallest data unit in dot codes to beprinted on the printing medium and modifies the parameter data relatingto the resolution and specified by the resolution parameter specifyingmeans according to estimation of the estimating means.

Thus, while the shape of printed dots may vary depending on the type ofpaper to be used for the dot code output, the dot pitch and the dotshape may be optimized so as to accommodate the variance.

Printing ink can be blurred depending on the type of paper and printeddots can show a tendency of being thinned. If these problems areanticipated from the type of paper to be used, a relatively big patternmay be selected for dots to offset the problems.

(19) The coded data output apparatus according to (1), wherein theresolution parameter modifying means modifies the parameter datarelating to the resolution and specified by the resolution parameterspecifying means so as to optimize the shape of each dot constitutingthe smallest data unit in dot codes when dot codes are optically takenin by the image pick-up apparatus with a pixel interval having apredetermined aspect ratio.

Thus, dots can always be read with an optimal sampling ratio byspecifying the shape of printed dot to be used for correcting the shapeof the dots taken up with a pixel interval having an aspect ratio equalto that of the image pick-up apparatus.

(20) The coded data output apparatus according to (1), wherein theresolution parameter modifying means includes: pixel arrangementspecifying means for specifying the pixel arrangement to be assigned toeach dot constituting the smallest data unit in dot codes so as tooptimize the shape of each dot constituting the smallest data unit indot codes when dot codes are optically taken in by the image pick-upapparatus with a pixel interval having a predetermined aspect ratio; anddot interval specifying means for specifying a dot interval for each dotconstituting the smallest data unit in dot codes.

Thus, the shape of printed dot can be specified to correct the shape ofthe dots taken up with a pixel interval having an aspect ratio equal tothat of the image pick-up apparatus.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative devices shown anddescribed herein. Accordingly, various modifications may be made withoutdeparting from the spirit and scope of the general inventive concept asdefined by the appended claims and their equivalents.

We claim:
 1. A coded data output apparatus for producing image data of adot code and supplying the image data to a plate making apparatus whichis used to print the image data onto a printing medium as, said dot codeincluding a plurality of dots arranged in correspondence to data to berecorded and being optically read by a reading device, whereby the datais reproduced based on arrangement of the dots, said coded data outputapparatus comprising:image acquisition means for inputting or generatingdata as an image of a dot code to be printed to acquire image data;resolution parameter specifying means for specifying parameter datarelating to the resolution of the image data acquired by said image dataacquisition means; resolution parameter modifying means for modifyingthe resolution-related parameter data specified by said resolutionparameter specifying means according to the resolution-relatedcharacteristics of said plate making apparatus; and image data outputmeans for outputting image data acquired by said image acquisition meansto said plate making apparatus in accordance with the resolution-relatedparameter data modified by said resolution parameter modifying means,said resolution parameter modifying means preventing image distortiondue to re-sampling when the resolution parameter modifying meansexecutes a modification according to the resolution-relatedcharacteristics of the plate making apparatus.
 2. The coded data outputapparatus according to claim 1, wherein said resolution parametermodifying means includes:pixel arrangement specifying means forspecifying a pixel arrangement for pixels to be assigned to each dotconstituting the smallest data unit in dot codes to be printed on saidprinting medium according to said resolution-related characteristics inorder to modify the parameter data relating to the resolution andspecified by said resolution parameter specifying means; and dotinterval specifying means for specifying the dot interval for dotsconstituting the smallest data unit in dot codes to be printed on saidprinting medium according to said resolution-related characteristics. 3.The coded data output apparatus according to claim 2, wherein said pixelarrangement specifying means further includes a reference table to bereferred to for determining the pixel arrangement for pixels to beassigned to each dot constituting the smallest data unit in dot codes tobe printed on said printing medium on the basis of the parameter datarelating to the resolution and specified by said resolution parameterspecifying means and said resolution-related characteristics so that anoptimal pixel arrangement may be selected according to saidresolution-related characteristics by referring to said reference table.4. The coded data output apparatus according to claim 2, wherein saiddot interval specifying means further includes a reference table to bereferred to for determining the pixel interval for pixels to be assignedto each dot constituting the smallest data unit in dot codes to beprinted on said printing medium on the basis of the parameter datarelating to the resolution and specified by said resolution parameterspecifying means and said resolution-related characteristics so that anoptimal pixel interval may be selected according to saidresolution-related characteristics by referring to said reference table.5. The coded data output apparatus according to claim 2, wherein saidpixel arrangement specifying means specifies an optimal pixelarrangement by modifying the geometrical arrangement of pixels for eachdot when specifying the pixel arrangement for pixels to be assigned toeach dot constituting the smallest data unit in dot codes to be printedon said printing medium.
 6. The coded data output apparatus according toclaim 5, wherein said pixel arrangement specifying means specifies anoptimal pixel arrangement by modifying the geometrical arrangement ofpixels for each dot in such a way that the diameter of each dotconstituting the smallest data unit in dot codes to be printed on saidprinting medium is smaller than the ideal distance separating adjacentdots.
 7. The coded data output apparatus according to claim 6, whereineach dot is formed by arranging a number of pixels in such a way thatthe diameter of each dot specified by said pixel arrangement specifyingmeans is greater than a half of the ideal distance separating adjacentdots.
 8. The coded data output apparatus according to claim 6, whereineach dot is formed by arranging a number of pixels in such a way thatthe surface area of each dot specified by said pixel arrangementspecifying means is between 50% and 80% of the square of the idealdistance separating adjacent dots.
 9. The coded data output apparatusaccording to claim 2, wherein said dot interval specifying meansspecifies a dot interval in such a way that the dot interval of the dotsto be printed on said printing medium is equal to the smallest pixelinterval of said plate making apparatus multiplied by an integer. 10.The coded data output apparatus according to claim 2, wherein said dotinterval specifying means specifies a dot interval such that the dotinterval is optimal in relation to a sampling theorem when image pick-upapparatus of the reading device reads said dot codes as being discreteby a predetermined interval.
 11. The coded data output apparatusaccording to claim 10, wherein the dot interval specified by said dotinterval specifying means satisfies the formula of ##EQU5## where n isthe pitch of the smallest pixels of said plate making apparatus (n:integer), R is the resolution [lines/mm] of said plate making apparatus,M is the optical magnification of said image pick-up means and X is thepixel interval of said image pick-up means when said coded data outputapparatus outputs image data.
 12. The coded data output apparatusaccording to claim 10, whereineach of said dot codes of is formed bytwo-dimensionally arranging a plurality of blocks, each comprising adata dot pattern arranged in correspondence to the data to be recorded,and a marker arranged with a predetermined positional relationship withthe data dot pattern and used for determining a reference point for theoperation of reading the data dot pattern: and said dot intervalspecifying means specifies a dot interval in such a way that the numberof said block is maximized in the light receiving plane of said imagepick-up means.
 13. The coded data output apparatus according to claim 1,whereineach of said dot codes is formed by two-dimensionally arranging aplurality of blocks, each comprising a data dot pattern arranged incorrespondence to the the data to be recorded, and a marker arrangedwith a predetermined positional relationship with the data dot patternand used for determining a reference point for the operation of readingthe data dot pattern; and said resolution parameter modifying meansfurther includes marker position correcting means for correcting theposition of said marker relative to said data dot pattern according tothe modification of the parameter data relating to the resolution andspecified by said resolution parameter specifying means according to theapplied resolution-related characteristics specific to said plate makingapparatus.
 14. The coded data output apparatus according to claim 13,wherein said marker position correcting means is further includes amarker correction table specifying the relationship between theresolution-related characteristics specific to said plate makingapparatus and the pixels constituting said marker so that it correctsthe pixel value by a 0.5 pixel unit by referring to the markercorrection table.
 15. The coded data output apparatus according to claim1, whereineach of said dot codes is formed by two-dimensionallyarranging a plurality of blocks, each comprising a data dot patternarranged in correspondence to the data to be recorded, and a markerarranged with a predetermined positional relationship with the data dotpattern and used for determining a reference point for the operation ofreading the data dot pattern; and said image data output means includesblock arrangement specifying means for causing the direction of theblocks constituting said dot codes agree with the direction of saidpixel arrangement of said plate making apparatus if it recognizes thatthe direction of said pixel arrangement does not agree with thelongitudinal direction of the dot codes to be printed when it outputsthe image data corresponding to said dot codes.
 16. The coded dataoutput apparatus according to claim 1, whereineach of said dot codes isformed by two-dimensionally arranging a plurality of blocks, eachcomprising a data dot pattern arranged in correspondence to the data tobe recorded, and a marker arranged with a predetermined positionalrelationship with the data dot pattern and used for determining areference point for the operation of reading the data dot pattern; andsaid image data output means includes dot interval regulating means forregulating the dot code interval so as not to cause dot code readingerrors to occur if the image data corresponding to said dot codes arere-sampled by the pixel interval of the plate making apparatus if itrecognizes that the direction of said pixel arrangement of said platemaking apparatus does not agree with the longitudinal direction of thedot codes to be printed when it outputs the image data corresponding tosaid dot codes.
 17. The coded data output apparatus according to claim16, wherein said dot interval regulating means includes means forregulating the dot code interval without altering the direction of saiddot codes and the direction of said blocks.
 18. The coded data outputapparatus according to claim 2, wherein said resolution parametermodifying means includes means for estimating the shape of each dotconstituting the smallest data unit in dot codes to be printed on saidprinting medium and modifies the parameter data relating to theresolution and specified by said resolution parameter specifying meansaccording to estimation of said estimating means.
 19. The coded dataoutput apparatus according to claim 1, wherein said resolution parametermodifying means modifies the parameter data relating to the resolutionand specified by said resolution parameter specifying means so as tooptimize the shape of each dot constituting the smallest data unit indot codes when dot codes are optically taken in by the image pick-upapparatus as a pixel having a predetermined aspect ratio.
 20. The codeddata output apparatus according to claim 19, wherein said resolutionparameter modifying means includes:pixel arrangement specifying meansfor specifying the pixel arrangement to be assigned to each dotconstituting the smallest data unit in dot codes so as to optimize theshape of each dot constituting the smallest data unit in dot codes whendot codes are optically taken in by the image pick-up apparatus as apixel having a predetermined aspect ratio; and dot interval specifyingmeans for specifying a dot interval for each dot constituting thesmallest data unit in dot codes.